From 8f00b1fdad0c60220625bace86510db125ecf31a Mon Sep 17 00:00:00 2001
From: Boxy <rust@boxyuwu.dev>
Date: Thu, 10 Apr 2025 17:48:33 +0100
Subject: Allow parenthesis around inferred array lengths

---
 compiler/rustc_ast_lowering/src/lib.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

(limited to 'compiler/rustc_ast_lowering/src')

diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs
index 6aa6a18ee9a..f62d250fcbe 100644
--- a/compiler/rustc_ast_lowering/src/lib.rs
+++ b/compiler/rustc_ast_lowering/src/lib.rs
@@ -2034,7 +2034,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     }
 
     fn lower_array_length_to_const_arg(&mut self, c: &AnonConst) -> &'hir hir::ConstArg<'hir> {
-        match c.value.kind {
+        // We cannot just match on `ExprKind::Underscore` as `(_)` is represented as
+        // `ExprKind::Paren(ExprKind::Underscore)` and should also be lowered to `GenericArg::Infer`
+        match c.value.peel_parens().kind {
             ExprKind::Underscore => {
                 if !self.tcx.features().generic_arg_infer() {
                     feature_err(
-- 
cgit 1.4.1-3-g733a5